Quick curing polyester resins



Patented Dec. 8, 1953 QUICK CURING POLYESTER RESINS 7 Peter Kass,Wilmington, and Baak W. Lew,

Arden, Del., assignors to Atlas Powder Company, Wilmington, DeL, acorporation of Delaware No Drawing. Application October 14, 1950, SerialNo. 190,240

This invention relates to polyester resins and more particularly tosolid, pulverulent polyester resins which are curable and which may becopolymerized with other polymerizable bodies.

In copending application Serial No. 92,746, filed May 11, 1949 by one ofus, there is disclosed a class of new and useful resins which arethermoplastic, high melting solids, sufliciently hard and friable atroom temperature that they may be pulverized and stored withoutblocking, autopolymerizable under the influence of known curingcatalysts and copolymerizable with styrene or other vinyl compounds toyield valuable casting and laminating resins. The so described resinsare basically polyesterification products of ethene dicarboxylic acidsand dihydric alcohols conforming to the formula wherein R is an alkyleneradical containing from 2 to 3 carbon atoms, A is a 2-alkylidene radicalcontaining from 3 to 4 carbon atoms, m and n are each at least one, andthe average sum of I m and n is not over 3.

In application Serial No. 190,239 filed of even date herewith by one ofus there is disclosed a class of resins of improved resistance to heatdistortion which are basically linear polyesters of ethene dicarboxylicacids with mixed diols,

We accomplish this object by producing polyesters from substantiallystoichiometric amounts of an ethene dicarboxylic acid and a mixed polyolconsisting of (a) at least 50 mol per cent of a diol conforming to theformula wherein the symbols have the meanings ascribed to themhereinbefore; (b) from about 1 to about mol per cent of an aliphaticpolyhydric alcohol containing from 3 to 6 carbon atoms and at 12 Claims.(c1. zoo-45.4)

2 least 3 hydroxyl groups, and (c) from 0 to about 49 mol 'per cent of alower alkylene glycol selected from the group consisting of ethyleneglycol, diethylene glycol, propylene glycol and dipropylene glycol. Thesaid ethene dicarboxylic acids are fumaric acid and maleic acid. Thepolyesters of our invention may be esters of either of these acids or ofa mixture of the two. Throughout this specification and in the appendedclaims the term dicarboxylic acids is to be understood to includeanhydrides of such acids where such anhydrides exist, and derivatives ofsuch acids which yield dicarboxylic acid radicals under esterifyingconditions. For example, lower alkyl esters of the dicarboxylic acidsare full equivalents of the acids themselves for purposes of thisapplication.

Diols conforming to the formula cited above, and useful in preparing thequick curing resins of the present invention, are fully described in theabovementioned earlier copending application, wherein methods for theirpreparation are also indicated. Among such diols we may mentionspecifically 2.2-di-(4-beta hydroxyethoxyphenyl) propane, 2.2di-(4-beta,hydroxyethoxyphenyD-butane, the polyoxyethylene ether of isopropylidenediphenol wherein both phenolic hydroxyls are oxyethylated and theaverage number of oxyethylene groups per mol is 2.6, thepolyoxypropylene ether of Z-butylidene diphenol wherein both phenolichydroxyls are oxyalkylated and the average number of oxypropylene groupsper mol is 2.5.

As the second named component of the mixed polyol of the polyesterresins of our invention we employ higher polyhydric alcohols, that is,

polyhydric alcohols of functionality greater than 2. They are selectedfrom the aliphatic polyhydric alcohols containing from 3 to 6 carbonatoms and at least 3 hydroxyl groups, among which compounds may be namedglycerol, pentaerythritol, sorbitol, mannitol, sorbitan, erythritol, andthe like. Of the compounds so defined glycerol is the preferred species.As the content of said higher polyhydric alcohol in the mixed polyolincreases, the rate of autopolymerization of the resulting resin underthe influence of the usual curing catalysts is increased. If excessiveamounts are employed; however, there is a tendency for the resins to gelin the reaction vessel before polyesterification has been carried to asatisfactory extent. To avoid such esterifying polyol, and preferablyemploy not hours. A vacuum of '15 mm. was then applied andthe reactioncontinued for 3 hours at 185 C. The product of the reaction was a hard,friable, clear resin, tan in color, with an acid number of 23 and amelting point of 110C;

The effect on the curing rate of incorporating successively greateramounts of a higher functional polyhydric alcohol in polyesters whereinthe diol is a dihydroxyalkylene ether of bis'phenol is'indicated inTable I. A series of resins were prepared employing fumaric acid as theethene dicarboxylic acid and the polyoxypropylene ether ofisopropylidene diphenol containing two oxypropylene groups permol asthediol. The several resins were modified by incorporating from 0 to molper cent of pentaerythritol in the essterifying polyol in accordancewith the hereinbefore described technique. The rate of cure of eachresin was determined by intimately mixing it in powdered form with 4% ofits own weight of stannic chloride pentahydrate and placing a smallquantity of the mixture on a metal plate maintained at a temperature of200 C. The time required for the resin to undergo cure is tabulated, theranges of times indicating the period from the first evidence ofgelation to the development of complete infusibility. In the table theresins are further characterized by their melting points.

TABLE I Curing Time in Seconds Mol Percent P. E. in Esteriiying Polyol60 to 120. to 50. 15 to 30. 10 to 20.

Table II shows the effect of 4 mol per cent of glycerol on the cure timewhen replacing an equivalent quantity of the diol, 2.2-di-(beta hydroxyethoxy phenyD-propane in a fumarate polyester as the extent ofesterification is varied by reacting to successively higher meltingpoints. The cure time was determined as described hereinbefore.

It is apparent that for a resin of given melting point the modificationshown approximately halves the curing time. The increased curing rate soobtained is of decided importance in the utilization of the resins underconsideration, and may well represent the difierence between utility andnon-utility in many applications.

The quick curing resins made in accordance with our invention are 9fespecial utility in the preparation of resinous mats of felted fibrousmaterials, such for example, as glass fibers. The resin intimately mixedwith a suitable curing catalyst may be deposited in the felt by anysuitable means, such, for example, as drawing the latter through achamber in which a suspension of the powdered resin-catalyst mixture ismain- 6 tained by aturbulent air flow. Upon subsequent passage of thefelt through a curing chamber at elevated temperature the resin is firstmelted then cured to the insoluble-infusible state, cementing the fiberstogether at points of inter section in the felt.

It will be obvious to those skilled in the art that minor modificationscan be made in the polyester resins herein disclosed without departingfrom the spirit of the invention. The physical properties of the resinmay be modified, for example,-by replacing a minor proportion of theethene dicarboxylic acid radical with a stoichiometrically equivalentamount of a different acid radical saturated or unsaturated, polybasic'or monobasic. Similarly, minor proportions of the alcohol radical may bereplaced by stoichiometric quantities of other alcohols, monohydric orpolyhydric. Resins so modified are the full equivalent of the unmodifiedresins described in detail provided the resin consists essentially ofthe esterification product of the named dicarboxylic acids and mixedpolyols, reacted to the extent that the products are thermoplastic, hardand friable at ordinary temperatures, with melting points of C. orhigher.

It has been mentioned hereinbefore, that the quick curing polyesterresins here disclosed may be copolymerized with polymerizable vinylcompounds. Among such copolymers are the insoluble, infusible resinousproducts obtained by copolymerizing, under curing conditions, from about25% to about 75% by weight of a polymerizable monomeric vinyl compoundand from about 75% to 25% of saidpolyester. More particularly, attentionis directed to such insoluble, infusible resinous products wherein thesaid polyester has a melting point of at least C., and is a 1,2dicarboxy ethene ester of a mixed polyol consisting of (a) at least 50mol percent of a diol conforming to the formula hereinbefore presented,(b) about 4 mol percent of glycerol, and (c) from 0 to about 46 molpercent of ethylene glycol. A specific example of such a copolymer isthat from about 40% of styrene with about 60% of the fumarate of a mixedpolyol consisting of about 71 mol per cent of 2,2 di- (4 hydroxy propoxyphenyD-propane, about 4 mol percent of glycerol and about 25 mol percentofethylene glycol. 7

Having described our invention indetail and having illustrated specificembodiments thereof we claim:

1. A thermoplastic, curable, resinous esterification product of1,2-dicarboxy ethene with a substantially stoichiometrically equivalentquantity of a mixed polyol consisting of (a) at least 50 mol per cent ofa diol conforming to the formula wherein R is an alkylene radical havingfrom 2 to 3 carbon atoms, A is a 2-alkylidene radical having from 3 to 4carbon atoms, m and n are each at least one and the average sum of m andn is not over 3, (b) from about 1 mol per cent to about 10 mol per centof a polyhydric alcohol containing from 3 to 6 carbon atoms and at least3 hydroxyl groups, and (c) from 0 to 49 mol per cent of a lower glycolselected from the group consisting of ethylene glycol, diethyleneglycol, propylene glycol and dipropylene glycol, said product having amelting point of at least 80 C.

aceagovo 2.' A:vthermoplastic, curable re'sinous esterincationuproductof LZ-dicarbom ethene 'withsa substantially sto-ichiometricallyequivalent quantity of a mixedipolyol consisting of from about 99-mo1percent to about 90 molatper- -centofaa diol conforming to the formula:mon-tpo -ga-gocnonn wherein ,R is an -alkylene radical having from 2--to 3 carbon atoms, A is a 2-alkylidene radical having from 3-to 4carbon atoms, m and mare each at least one, and the average. sumof and nis not over 3; and from about one mol per cent to about mol per cent-of:a'polyhydric alcoholcontaining from 3 1:06 carbon atoms and at least 3hydroxyl groups,said product having a melting point of at least=90 C.

3. A thermoplastic',curable, resinous'esterification product of1,2-di'carboxy ethene withva 'sub-. stantially 'stoichiometricallyequivalent quantity of'a mixed polyol consisting of from about 98 toabout 94 mol per cent of a diol conformingto the formula wherein R is.an alkylene radical having from 2 to 3 carbon atoms, A is a 2-alkylidenehaving from 3 to 4 carbon atoms, m and n are each at least one, and theaverage sum. of m and n is not over 3; and from about 2 to about 6 molpercent of glycerol, said product having a melting point of at least 90C.

4. A thermoplastic, curable, resinous esterification product of fumaricacid-with a substantially stoi'chiometrically equivalent, quantity of amixed polyol consisting of about 96 mol per cent of 2.2- di-( l-betahydroxy ethoxy phenyl).-propane and about 4 mol per cent of. glycerol,said. product having a melting point of at 1east90"C.

1 5. A thermoplastic, curable, resinous esterification product of1,2-dica'rboxy ethene withasubstantially stoichiometrically J equivalentquantity of a mixed polyol consisting of (a) at least 50 mol per cent ofa diol conforming to the formula wherein R is an alkylene radicalhavingfromz to 3 carbon atoms, A is a 2-alkylidene" radical having from3 to 4 carbon'atoms, m and n are each at least 1 and the average sum ofm-andn is not over 3, (b) from about 2 to about'6 mol per cent of Ipolyhydric alcohol containing from 3 to 6 carbon atoms and at least'3*hydroxyl groups, and (c) from Oto about-4811101 per cent of ethyleneglycol, said product having ainelting point'of at least 90 'C.

8 6. A th'ermopla'stic,"curable, resinous esteriii'ca tionproduct. of1,2:-.dicarboxy 'ethene witl'ra; substantially stoichiometricallyequivalent quantity of amixed polyol consisting of (a): at least 50 molper cent of a diol'conforming to'the formula whereinR isan alkyleneradical having from 2 to 3 carbon atoms,-A*isa 2-alkylidene radicalhaving from 3 to 4 carbon-atoms, m and'n are -each at least one andtheavera ge sum-ofmandm is not overj3, (b)' about 4 mol per cent'ofglycerol; and (0) from 0 to about 46 mol per centofethylenegglycol; saidproduct having ameltii'ig point of at least 90 C. V

"7; A thermoplastic, curable, resinous 'esterifi'cation product offumaric acid with a substantially stoichiometrically equivalent'quantityof amixed polyol consisting of about '71. molrper cent of 2.2-di (4hydroxy propoxy phenyl) -propane about 4mol per cent of glycerol; andabout 25 mol-per cent of ethylene glycol, said product 'having'a meltingpoint of at least 90 C.

8. The insoluble, infusible resinous product obtained by heating theproduct of claimiliunder curing conditions.

9. The insoluble, infusible resinousproduct-obtained by heating theproduct of claim 4-und'er curing conditions.

10. The insoluble, infu'sible resinous product obtained by:copolymerizing, under curing conditions, from about 75% to about 25%. byweight of the product of claim 1 with from about 25% to about 75% byweight of' a polymerizable' monomeric vinyl compound.

'11. The insoluble infusible resinous product resulting from thecopolymerization under curing conditions, of from about 75% to about'25%by weight of the product'of'claim fiwith fromabout 25% to about 75% byweight of a'polymerizable vinyl monomer.

-12. The insoluble, infusible resinousproduct resulting from thecopolymerizatiomunder curing conditions, of about-%'of the product ofclaim '7 with-about 40 of styrene.

PETER KASS. BAAK W. LEW.

References Cited in'the file' of this patent UNITED STATES PATENTSNumber' Name "Date 2,437,046 *Rothrock et a1. Mar. 2, '1948 2,511,621Condit June 13, 1950 OTHER REFERENCES Schmidt &-Marlies,- Principles ofHigh Polymer Theory 8: Practice, McGraw Hill, 1948, page623.

1. A THERMOPLASTIC, CURABLE, RESINOUS ESTERIFICATION PRODUCT OF 1,2-DICARBOXY ETHENE WITH A SUBSTANTIALLY STOICHIOMETRICALLY EQUIVALENT QUANTITY OF A MIXED POLYOL CONSISTING OF (A) AT LEAST 50 MOL PER CENT OF A DIOL CONFORMING TO THE FORMULA
 10. THE INSOLUBLE, INFUSIBLE RESINOUS PRODUCT OBTAINED BY COPOLYMERIZING, UNDER CURING CONDITIONS, FROM ABOUT 75% TO ABOUT 25% BY WEIGHT OF THE PRODUCT OF CLAIM 1 WITH FROM ABOUT 25% TO ABOUT 75% BY WEIGHT OF A POLYMERIZABLE MONOMERIC VINYL COMPOUND. 